help fixing an issue w/ multiplayer

I've been trying to play on multiplayer for months and I literally cannot get it to work. I made my Minecraft account about 5 years ago, when I was 10, and I made the mistake of putting my actual age when I set it up. Now, it won't let me play multiplayer, and I'm assuming that has something to do with it- like there's some sort of restrictions on the account because of my age that microsoft automatically put on that it won't let me change? 

When I open up Minecraft (java btw, idk if that changes anything), the multiplayer button is all greyed out and says "Multiplayer is disabled, please check your Microsoft account settings". I dont even know wtf the microsoft account settings they're talking about are. I couldnt find anything microsoft account that would let me fix it, or that was even remotely related. I've tried to get my dad to help out by opening up his account because I'm pretty sure he's like the parent/guardian for my account since im a minor, but nothing has worked so far. He turned off the restrictions he saw, built I still can't play multiplayer. Maybe there was another page we didnt see or something?

I'm not trying to jailbreak my account or anything, I just wanna figure out how I can help my dad help me to get multiplayer to work out again. I used to be able to play multiplayer until I think a few months ago, when it just stopped letting me in.

Idk, I'm just wondering if anyone has any ideas for things me or my dad could do to fix this issue, or if anyone has had the same problem and maybe found a way around it.